Very interested discussion about Test Driven Design approach; is it productive ore over complex.. Raises a lot of ideas and gives a lot of different opinions.. Check it out

Eli Lopian, the guy who runs TypeMock.NET(An amazing Mocking product, BTW – a bit too powerful for it’s own good, perhaps) and myself share what seem to be conflicting views on how “Testable” object Oriented applications should be out of the box that is, should or shouldn’t you be considering Testability when designing your software, and how much would you let Testability considerations change your design (add interfaces, exposes some methods, allow polymorphism etc..).